U.S. patent number 10,753,378 [Application Number 16/080,498] was granted by the patent office on 2020-08-25 for fluid-actuated diaphragm drive, and valve arrangement which is equipped therewith.
This patent grant is currently assigned to FESTO SE & Co. KG. The grantee listed for this patent is FESTO SE & Co. KG. Invention is credited to Harald Rohrig, Andreas Weisang.
United States Patent |
10,753,378 |
Rohrig , et al. |
August 25, 2020 |
Fluid-actuated diaphragm drive, and valve arrangement which is
equipped therewith
Abstract
A fluid-actuated diaphragm drive and a valve arrangement which
is equipped therewith, wherein the diaphragm drive has a drive
housing with two drive housing parts which are attached to one
another axially. An insert body which preferably consists of
plastic material and delimits at least one length section of an
operating chamber which can be loaded with a fluid is inserted into
each of the drive housing parts, wherein a drive diaphragm which is
movement-coupled to an output member is clamped in between the two
insert bodies. A seal structure which is active between at least
one of the insert bodies and the drive housing is capable of
preventing an axial flow around the two insert bodies in the region
which lies radially between them and the drive housing.
Inventors: |
Rohrig; Harald
(Spiesen-Elversberg, DE), Weisang; Andreas (Gersheim,
DE) |
Applicant: |
Name |
City |
State |
Country |
Type |
FESTO SE & Co. KG |
Esslingen |
N/A |
DE |
|
|
Assignee: |
FESTO SE & Co. KG
(Esslingen, DE)
|
Family
ID: |
56567565 |
Appl.
No.: |
16/080,498 |
Filed: |
July 11, 2016 |
PCT
Filed: |
July 11, 2016 |
PCT No.: |
PCT/EP2016/066400 |
371(c)(1),(2),(4) Date: |
August 28, 2018 |
PCT
Pub. No.: |
WO2018/010760 |
PCT
Pub. Date: |
January 18, 2018 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20190063470 A1 |
Feb 28, 2019 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F16K
31/1262 (20130101); F16K 31/126 (20130101); F15B
15/10 (20130101); F15B 13/0407 (20130101) |
Current International
Class: |
F16K
31/126 (20060101); F15B 15/10 (20060101); F15B
13/04 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
|
|
|
|
|
103443477 |
|
Dec 2013 |
|
CN |
|
105408640 |
|
Mar 2016 |
|
CN |
|
102007059922 |
|
Jun 2009 |
|
DE |
|
102013016350 |
|
Jan 2015 |
|
DE |
|
2028377 |
|
Feb 2009 |
|
EP |
|
2799747 |
|
Nov 2014 |
|
EP |
|
Primary Examiner: Lopez; F Daniel
Attorney, Agent or Firm: Hoffman & Baron, LLP
Claims
The invention claimed is:
1. A fluid-actuated diaphragm drive comprising a drive housing with
two drive housing parts, which are attached to one another axially
in a joining region while together bounding a housing interior,
wherein a drive diaphragm, which separates two axially adjacent
operating chambers from each other in a fluid-tight manner and
which is motion-coupled to an output member is located in the
housing interior, wherein the drive diaphragm is axially
deflectable by the application of fluid to at least one of the
operating chambers in order to induce an output movement of the
output member, said application of fluid being controllable by
means of a control passage structure, which is formed at least
partially in the drive housing, and wherein the drive diaphragm is
axially clamped in a sealing manner all around at its outer edge
section between insert bodies, which are separate from the drive
housing, each of which insert bodies is inserted into one of the
two drive housing parts and forms a peripheral wall section
adjoining the drive diaphragm of the associated operating chamber,
wherein a seal structure is located radially between at least one
of the insert bodies and the drive housing for radially sealing
between the at least one of the insert bodies and the drive
housing, and wherein the seal structure comprises a plurality of
annular seal sections arranged coaxially and at an axial distance
from one another.
2. A diaphragm drive according to claim 1, wherein the seal
structure is designed separately from the insert bodies and from
the drive housing.
3. The diaphragm drive according to claim 1, wherein two axially
spaced annular seal sections are assigned to at least one insert
body.
4. A fluid-actuated diaphragm drive comprising a drive housing with
two drive housing parts, which are attached to one another axially
in a joining region while together bounding a housing interior,
wherein a drive diaphragm, which separates two axially adjacent
operating chambers from each other in a fluid-tight manner and
which is motion-coupled to an output member is located in the
housing interior, wherein the drive diaphragm is axially
deflectable by the application of fluid to at least one of the
operating chambers in order to induce an output movement of the
output member, said application of fluid being controllable by
means of a control passage structure, which is formed at least
partially in the drive housing, and wherein the drive diaphragm is
axially clamped in a sealing manner all around at its outer edge
section between insert bodies, which are separate from the drive
housing, each of which insert bodies is inserted into one of the
two drive housing parts and forms a peripheral wall section
adjoining the drive diaphragm of the associated operating chamber,
wherein a seal structure is located radially between at least one
of the insert bodies and the drive housing for radially sealing
between the at least one of the insert bodies and the drive
housing, and wherein the two insert bodies are axially clamped
together and to the drive diaphragm located in between without any
direct clamping connection only by the axial pressure applied by
the drive housing parts accommodating them.
5. The diaphragm drive according to claim 4, wherein each insert
body has at least one support section, which is axially remote from
the other insert body and against which the associated drive
housing part bears with a mating support section, wherein the two
drive housing parts are axially clamped together by clamping means
acting between them, whereby the two insert bodies supported on the
drive housing parts are clamped together as well.
6. A fluid-actuated diaphragm drive comprising a drive housing with
two drive housing parts, which are attached to one another axially
in a joining region while together bounding a housing interior,
wherein a drive diaphragm, which separates two axially adjacent
operating chambers from each other in a fluid-tight manner and
which is motion-coupled to an output member is located in the
housing interior, wherein the drive diaphragm is axially
deflectable by the application of fluid to at least one of the
operating chambers in order to induce an output movement of the
output member, said application of fluid being controllable by
means of a control passage structure, which is formed at least
partially in the drive housing, and wherein the drive diaphragm is
axially clamped in a sealing manner all around at its outer edge
section between insert bodies, which are separate from the drive
housing, each of which insert bodies is inserted into one of the
two drive housing parts and forms a peripheral wall section
adjoining the drive diaphragm of the associated operating chamber,
wherein a seal structure is located between at least one of the
insert bodies and the drive housing, and wherein the two insert
bodies together with the drive housing form at least one fluid duct
chamber belonging to the control passage structure.
7. The diaphragm drive according to claim 6, wherein the two insert
bodies are designed to be annular while framing a ring interior
space, wherein the control passage structure opens into the ring
interior space so that the controlled application of fluid of the
drive diaphragm takes place through the ring interior space
enclosed by the two insert bodies.
8. The diaphragm drive according to claim 6, wherein each of the
two insert bodies together with the associated drive housing part
of the two drive housing parts forms a part of the at least one
fluid duct chamber belonging to the control passage structure.
9. The diaphragm drive according to claim 6, wherein the control
passage structure has a connecting port located on the one axial
side of the drive diaphragm on the outside of the drive housing and
usable for fluid infeed and fluid discharge, and wherein the
control passage structure is routed within of the drive housing by
means of the at least one fluid duct chamber to the other axial
side of the drive diaphragm, in order to communicate with the
operating chamber located there.
10. The diaphragm drive according to claim 6, wherein the two
insert bodies are designed to be annular, each having a front
annular opening and a rear annular opening axially opposite in
respect thereof, wherein their front annular openings face each
other.
11. The diaphragm drive according to claim 10, wherein the front
annular openings of the two insert bodies have a larger
cross-section than their rear annular openings.
12. A fluid-actuated diaphragm drive comprising a drive housing
with two drive housing parts, which are attached to one another
axially in a joining region while together bounding a housing
interior, wherein a drive diaphragm, which separates two axially
adjacent operating chambers from each other in a fluid-tight manner
and which is motion-coupled to an output member is located in the
housing interior, wherein the drive diaphragm is axially
deflectable by the application of fluid to at least one of the
operating chambers in order to induce an output movement of the
output member, said application of fluid being controllable by
means of a control passage structure, which is formed at least
partially in the drive housing, and wherein the drive diaphragm is
axially clamped in a sealing manner all around at its outer edge
section between insert bodies, which are separate from the drive
housing, each of which insert bodies is inserted into one of the
two drive housing parts and forms a peripheral wall section
adjoining the drive diaphragm of the associated operating chamber,
wherein a seal structure is located between at least one of the
insert bodies and the drive housing, and wherein the two insert
bodies are designed to be annular, each having a radially inward
inner ring section forming a peripheral wall section of an
operating chamber and a radially outward outer ring section
coaxially enclosing the inner ring section, wherein the two ring
sections are integrally connected to each other at the front side
of the insert body facing the drive diaphragm.
13. The diaphragm drive according to claim 12, wherein each of the
insert bodies has a radial inner surface which forms the peripheral
wall section, the radial inner surface having a convex curvature
immediately after the drive diaphragm and a concave curvature
immediately thereafter.
14. The diaphragm drive according to claim 12, wherein an
intermediate space with a cross-section widening from the front
towards the rear of the insert body is formed radially between the
two ring sections.
15. A fluid-actuated diaphragm drive comprising a drive housing
with two drive housing parts, which are attached to one another
axially in a joining region while together bounding a housing
interior, wherein a drive diaphragm, which separates two axially
adjacent operating chambers from each other in a fluid-tight manner
and which is motion-coupled to an output member is located in the
housing interior, wherein the drive diaphragm is axially
deflectable by the application of fluid to at least one of the
operating chambers in order to induce an output movement of the
output member, said application of fluid being controllable by
means of a control passage structure, which is formed at least
partially in the drive housing, and wherein the drive diaphragm is
axially clamped in a sealing manner all around at its outer edge
section between insert bodies, which are separate from the drive
housing, each of which insert bodies is inserted into one of the
two drive housing parts and forms a peripheral wall section
adjoining the drive diaphragm of the associated operating chamber,
wherein a seal structure is located radially between at least one
of the insert bodies and the drive housing for radially sealing
between the at least one of the insert bodies and the drive
housing, and wherein the two drive housing parts are made of metal,
and the two insert bodies are made of a plastic material.
16. The diaphragm drive according to claim 15, wherein the seal
structure comprises one sealing ring or a plurality of sealing
rings wherein each sealing ring is arranged to be coaxial with the
insert bodies.
17. The diaphragm drive according to claim 15, wherein precisely
two axially spaced annular seal sections are assigned to the one
insert body and only one annular seal section is assigned to the
other insert body.
18. The diaphragm drive according to claim 15, wherein the seal
structure comprises an annular sealing ring held in a receptacle
groove formed in an outer radial circumferential surface of one of
the insert bodies, the receptacle groove having a radial opening
and being axially confined on both sides by the insert body,
whereby the seal structure seals only radially between the one of
the insert bodies and the drive housing.
19. A fluid-actuated diaphragm drive comprising a drive housing
with two drive housing parts, which are attached to one another
axially in a joining region while together bounding a housing
interior, wherein a drive diaphragm, which separates two axially
adjacent operating chambers from each other in a fluid-tight manner
and which is motion-coupled to an output member is located in the
housing interior, wherein the drive diaphragm is axially
deflectable by the application of fluid to at least one of the
operating chambers in order to induce an output movement of the
output member, said application of fluid being controllable by
means of a control passage structure, which is formed at least
partially in the drive housing, and wherein the drive diaphragm is
axially clamped in a sealing manner all around at its outer edge
section between insert bodies, which are separate from the drive
housing, each of which insert bodies is inserted into one of the
two drive housing parts and forms a peripheral wall section
adjoining the drive diaphragm of the associated operating chamber,
wherein a seal structure is located radially between at least one
of the insert bodies and the drive housing for radially sealing
between the at least one of the insert bodies and the drive
housing, and wherein the control passage structure communicates
with both of the two operating chambers, so that fluid can be
applied in a controlled manner to both operating chambers for
generating the output movement of the output member.
20. A fluid-actuated diaphragm drive comprising a drive housing
with two drive housing parts, which are attached to one another
axially in a joining region while together bounding a housing
interior, wherein a drive diaphragm, which separates two axially
adjacent operating chambers from each other in a fluid-tight manner
and which is motion-coupled to an output member is located in the
housing interior, wherein the drive diaphragm is axially
deflectable by the application of fluid to at least one of the
operating chambers in order to induce an output movement of the
output member, said application of fluid being controllable by
means of a control passage structure, which is formed at least
partially in the drive housing, and wherein the drive diaphragm is
axially clamped in a sealing manner all around at its outer edge
section between insert bodies, which are separate from the drive
housing, each of which insert bodies is inserted into one of the
two drive housing parts and forms a peripheral wall section
adjoining the drive diaphragm of the associated operating chamber,
wherein a seal structure is located radially between at least one
of the insert bodies and the drive housing for radially sealing
between the at least one of the insert bodies and the drive
housing, and wherein a spring device acting between the drive
diaphragm and the drive housing and preloading the drive diaphragm
into a home position is located in one of the operating
chambers.
21. A fluid-actuated diaphragm drive comprising a drive housing
with two drive housing parts, which are attached to one another
axially in a joining region while together bounding a housing
interior, wherein a drive diaphragm, which separates two axially
adjacent operating chambers from each other in a fluid-tight manner
and which is motion-coupled to an output member is located in the
housing interior, wherein the drive diaphragm is axially
deflectable by the application of fluid to at least one of the
operating chambers in order to induce an output movement of the
output member, said application of fluid being controllable by
means of a control passage structure, which is formed at least
partially in the drive housing, and wherein the drive diaphragm is
axially clamped in a sealing manner all around at its outer edge
section between insert bodies, which are separate from the drive
housing, each of which insert bodies is inserted into one of the
two drive housing parts and forms a peripheral wall section
adjoining the drive diaphragm of the associated operating chamber,
wherein a seal structure is located radially between at least one
of the insert bodies and the drive housing for radially sealing
between the at least one of the insert bodies and the drive
housing, and wherein the output member is designed to be rod-shaped
and slidably extends outwards through at least one of the drive
housing parts.
Description
This application claims priority based on an International
Application filed under the Patent Cooperation Treaty,
PCT/EP2016/066400, filed Jul. 11, 2016.
BACKGROUND OF THE INVENTION
The invention relates to a fluid-actuated diaphragm drive
comprising a drive housing with two drive housing parts which are
attached to one another axially in a joining region while together
bounding a housing interior, wherein a drive diaphragm, which
separates two axially adjacent operating chambers from each other
in a fluid-tight manner is located in the housing interior and is
motion-coupled to an output member wherein the drive diaphragm can
be deflected axially by the application of fluid, controllable by
means of a control passage structure formed at least partially in
the drive housing, to at least one of the operating chambers, in
order to induce an output movement of the output member.
The invention further relates to a valve assembly equipped with
such a fluid-actuated diaphragm drive.
A diaphragm drive of the above type is known from DE 10 2013 016
350 B3 and comprises a drive housing which is surrounded on its
outside by an additional shell housing for protection and which
defines a housing interior divided into two fluid-actuable
operating chambers by a drive diaphragm clamped between two drive
housing parts of the drive housing. By a controlled application of
fluid to at least one of the two operating chambers, the drive
diaphragm can be deflected axially in one or the other direction
for moving a rod-shaped output member attached to the drive
diaphragm. The fluid is applied by means of a control passage
structure which passes through the wall of the drive housing and
comprises a plurality of control passages which terminate into the
two operating chambers and through which a controlled supply and
discharge of a drive fluid can be provided.
From EP 2 028 377 A2, a diaphragm drive is known which can be used
as a drive source in a valve assembly and which has a housing in
which a diaphragm tightly joined to the housing by its radially
outer region is located. The diaphragm divides the housing interior
into two operating chambers, to one of which a pressure fluid can
be applied in a controlled manner while the other contains a spring
device supported between the diaphragm and the housing and
preloading the diaphragm and a valve spindle attached thereto
towards a home position.
SUMMARY OF THE INVENTION
The invention is based on the problem of creating measures
facilitating the optimised construction of a fluid-actuated
diaphragm drive.
To solve this problem, it is provided in a fluid-actuated diaphragm
drive of the type referred to above that the drive diaphragm is
clamped at its outer edge section, while forming a seal, all around
axially between insert bodies which are separate from the drive
housing, each of which is inserted into one of the two drive
housing parts and forms a peripheral wall section, adjoining the
drive diaphragm, of the associated operating chamber, wherein a
seal structure is located between at least one of the insert bodies
and the drive housing.
The problem is further solved by a valve assembly with a valve
fitting having a movable valve member and a with diaphragm drive
designed in the above manner, which is located thereon and serves
to actuate a valve member, and the output member of which is
motion-coupled to the valve member of the valve fitting.
Owing to the insert bodies installed into the drive housing, at
least those longitudinal sections of the two operating chambers
which directly adjoin the drive diaphragm axially are not bounded
directly by the drive housing but by one each of the insert bodies
installed into the drive housing and separate therefrom. It has
been shown that such separate insert bodies can be produced
considerably more easily and cost-effectively, even in complex
designs, than drive housings, which have to meet further
requirements, such as the provision of a control passage structure
through which the drive fluid required for the operation of the
diaphragm drive can be carried. It is, for example, possible to
shape the insert bodies such that the diaphragm can cling to them
while being deflected and is not damaged by sharp edges. It is
further advantageously possible to set up a series of diaphragm
drives which are as standard equipped with identical drive housing
parts fitted with suitably adapted insert bodies for the specific
tailoring of the individual diaphragm drives. If required, the
combination of the insert bodies with the drive housing parts
furthermore facilitates in intermediate regions the creation of
chambers which can be used for a fluid flow, in particular as parts
of the control passage structure. The seal structure acting between
the drive housing and one or both of the insert bodies expediently
prevents an axial flow-past of fluid in the region between the
insert bodies and the drive housing. The seal structure in
particular provides a fluid-tight bulkhead between axially adjacent
zones in the circumferential region of the insert bodies, so that a
transfer of a drive fluid used for the actuation of the diaphragm
drive and fed into one of the two operating chambers into the other
operating chamber is prevented. With the aid of the seal structure,
it is furthermore possible to define, if required, one or more
hollow spaces between the drive housing and the insert bodies,
which can be used for the passage of the drive fluid, particularly
easily.
Advantageous further developments of the invention emerge from the
dependent claims.
The seal structure sealing between the arrangement of insert bodies
and the drive housing is expediently designed separately from the
insert bodies and/or the drive housing and expediently comprises at
least one sealing ring, in particular an O-ring, arranged to be
coaxial with the insert bodies. The seal structure can comprise
only one such sealing ring or several sealing rings spaced axially
from one another. Each sealing ring forms a seal section which
seals against at least one insert body on the one hand and against
at least one drive housing part on the other hand.
Instead of an independent sealing ring, each seal section can
alternatively be designed as a sealing material coating fixed by
adhesive force, in particular by injection moulding, to an insert
body or to the drive housing part.
A seal section can also be represented directly by the outer radial
edge region of the drive diaphragm if the drive diaphragm is
designed such that it projects radially beyond the two insert
bodies on the outside and with its projecting edge section acts
together with the drive housing to form a seal.
The walls of the insert bodies are preferably designed without
openings. This facilitates a particularly simple production. Fluid
flows to be applied to the drive diaphragm therefore do not pass
through the walls of the insert bodies. The control passage
structure therefore preferably does not penetrate the walls of the
insert bodies.
In a preferred variant, precisely two axially spaced annular seal
sections are provided between one of the two insert bodies and the
associated drive housing part. In this context, it is expedient if
only a single annular seal section is assigned to the other insert
part. In principle, however, each insert body can cooperate with
precisely one seal section or with several seal sections of the
seal structure.
One preferred variant of the insert bodies provides for their
design as annular bodies. As a result, each insert body is axially
open towards the drive diaphragm on the one hand and towards the
opposite boundary wall of the associated operating chamber on the
other hand. This advantageously facilitates the supply and
discharge of the drive fluid required for application to the drive
diaphragm through the ring interior space enclosed by the annular
insert body and forming a longitudinal section of the associated
operating chamber.
If the insert bodies are annular, in particular, the end wall of
the associated operating chamber, which bounds it on the side
axially opposite the drive diaphragm, is formed by the drive
housing. This end wall is preferably located at an axial distance
from the maximum axial stroke range of the deflectable drive
diaphragm, so that a contact between the drive diaphragm and the
end wall formed by the drive housing is always prevented.
In principle, it would be possible to clamp the two insert bodies
together axially by clamping means acting between them, in order to
combine them to an insert body assembly while holding the drive
diaphragm clamped at the same time. It is, however, considerably
more cost-effective to produce the diaphragm drive without direct
clamping between the two insert bodies and by clamping the two
insert bodies to each other and to the drive diaphragm only by
means of the drive housing parts which accommodate them. When the
drive housing is assembled, the two drive housing parts are axially
clamped together by suitable clamping means, in particular locking
screws, in such a way that they act from opposite axial sides on
the two insert bodies and axially clamp them, together with the
drive diaphragm engaged in between. In this way, there is no need
for separate clamping measures acting between the insert bodies, so
that manufacturing and assembly costs can be saved.
Each insert body expediently comprises a support section which is
axially remote from the respectively other insert body and on which
the drive housing part equipped with the respective insert body
acts by means of a mating support section formed thereon.
In a preferred variant of the diaphragm drive, at least one and
preferably each insert body forms, together with the drive housing
part accommodating it, a fluid duct chamber belonging to the
control passage structure. With the aid of the seal structure, an
undesirable axial fluid transfer between axially adjacent regions
can be avoided. At least one and preferable each of the fluid duct
chambers is preferably an annular chamber arranged concentrically
around the associated insert body, so that the fluid flowing
therein can be distributed around the respective insert body. In
this context, it is advantageously possible to arrange sections of
the control passage structure formed in the wall of the drive
housing in such a way that they terminate in different
circumferential regions of a fluid duct chamber, so that the
routing of the fluid between different radial sides of the drive
unit can be changed by means of a fluid duct chamber. This, for
example, allows for a particularly simple bypassing of the
arrangement of insert bodies if drive fluid fed into the drive
housing on the one axial side of the drive diaphragm is to be
guided to the operating chamber on the opposite side of the drive
diaphragm.
In this way, a design is possible in particular in which the
control passage structure has a connecting port located on the one
axial side of the drive diaphragm on the outside of the drive
housing and usable for fluid feed and fluid discharge and in which
the control passage structure is routed within the drive housing
towards the other axial side of the drive diaphragm by means of at
least one fluid duct chamber, in order to communicate with the
operating chamber located there.
In annular insert bodies, it is advantageous if the mutually facing
front annular openings of the insert bodies have a larger
cross-section than the opposite rear annular openings. In this way,
a particularly advantageous shaping can be chosen for that
peripheral wall section of an operating chamber which is
represented by an insert body and by which the drive diaphragm can
be supported to protect it against excessive expansion.
A particularly expedient structure of the insert bodies provides
that the insert bodies are designed to be annular, each having a
radially inward inner ring section forming a peripheral wall
section of an operating chamber and a radially outward outer ring
section coaxially enclosing the inner ring section and being
substantially hollow-cylindrical. The two ring sections are joined
integrally to each other on the front side of the insert body
facing the drive diaphragm. The annular body of the insert body can
at least partially be approximately V-shaped if viewed in
cross-section, resulting in an intermediate space with a
cross-section widening from the front towards the rear of the
insert body radially between the two ring sections.
For the radial inner surface of that section of the insert body
which forms a peripheral wall section of an operating chamber, a
concave design is recommended on the side facing the operating
chamber. The transition region between this concave peripheral wall
section and the front side of the insert body expediently has a
convex curvature, the radius being relatively large to protect the
diaphragm against damage while it is being deformed.
The two drive housing parts are expediently made of metal, and an
aluminium material or stainless steel is preferably selected. The
insert bodies can likewise consist of metal but are preferably made
of a plastic material which, by injection moulding for example,
facilitates a particularly cost-effective production of insert
bodies of any complex design.
If the diaphragm drive is to be used as a double-acting diaphragm
drive, the control passage structure is realised in such a way that
it communicates with both operating chambers and a preferably
mutually independent, controlled fluid application is possible in
respect to both operating chambers.
A diaphragm drive of single-acting design can be realised
particularly easily by providing that the control passage
structure, insofar as it is used for fluidic activation,
communicates with only one of the two operating chambers or--if
communicating with both operating chambers--is used for only one of
the two operating chambers. In the other operating chamber, there
is in this case provided a spring device acting between the drive
diaphragm and the drive housing and preloading the drive diaphragm
and thus the drive member in a resiliently yielding manner into a
home position. In combination with an integration of the diaphragm
drive into a valve assembly, a valve assembly of the "normally
open" or "normally closed" type can optionally be realised.
The drive member is preferably designed to be rod-shaped and
arranged such that it passes outwards in a slidable manner through
at least one of the drive housing parts. A longitudinal section of
the drive member which projects from the drive housing can be used
for coupling to a movable valve member of a valve fitting if the
diaphragm drive is designed as a component of a valve assembly. If
required, the drive member can also be used as a display and/or
control means, with the aid of which the current position of the
drive member can be visualised or otherwise indicated and/or its
current position can be detected in order to be used as a position
signal by an electronic control unit.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is explained in greater detail below with reference
to the accompanying drawing, of which:
FIG. 1 is a perspective external view of a preferred embodiment of
the fluid-actuated diaphragm drive according to the invention,
FIG. 2 shows the diaphragm drive from FIG. 1 as viewed from the
axial underside in contrast to FIG. 1,
FIG. 3 is a longitudinal section through the diaphragm drive from
FIGS. 1 and 2 along the sectional plane III-III from FIG. 1, with a
valve fitting on which the diaphragm drive can be mounted to form a
valve assembly indicated by a dot-dash line at the lower end of the
diaphragm drive,
FIG. 4 is a longitudinal section through the diaphragm drive from
FIGS. 1 to 3 along the sectional plane IV-IV, and
FIG. 5 is a longitudinal section through the diaphragm drive in a
sectional plane corresponding to FIG. 3 and in an exploded
view.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 3 shows a valve assembly identified in its entirety by the
reference number 1 and composed of a fluid-actuated diaphragm drive
2 shown in longitudinal section and a valve fitting 3, which is
equipped with this diaphragm drive 2 and only indicated by dot-dash
lines. FIGS. 1, 2, 4 and 5 show the diaphragm drive 2 without the
associated valve fitting 3. Together with the valve fitting 3, the
valve assembly 1 preferably forms a process valve assembly which
can be used in process control, e.g. in chemical and biochemical
applications.
The diaphragm drive 2 is suitable for other drive applications as
well, e.g. for use in production and assembly technology.
The diaphragm drive 2 has a housing 5, which is hereinafter
identified as drive housing 5. The drive housing 5 is in particular
a part of a drive unit 4 with a longitudinal axis 6, which is the
longitudinal axis of the drive housing 5 as well.
The drive housing 5 has a drive housing wall 7, which encloses a
housing interior 8 and which expediently also defines the outer
surface of the drive housing 5, which can be seen from the
outside.
In the housing interior 8, there is provided an elastically
deformable diaphragm identified as drive diaphragm 12, which
preferably consists of a material with rubber-elastic properties.
The drive diaphragm 12 extends transversely to the longitudinal
axis 6 and axially divides the housing interior 8 into two
sub-chambers identified as first operating chamber 13 and second
operating chamber 14. The drive diaphragm 12 is fluid-tight and
therefore prevents a fluidic communication between the two
operating chambers 13, 14.
The drive housing 5 is divided into two axially consecutive housing
parts identified hereinafter as first drive housing part 15 and
second drive housing part 16. In a joining region 17 extending
transversely and in particular at right angles to the longitudinal
axis 6, the two drive housing parts 15, 16 are fitted to each other
axially, preferably with the interposition of a housing seal
18.
With the aid of clamping means 22, which may be locking screws in
particular, the two drive housing parts 15, 16 are axially clamped
together in the joining region 17, so that they form a coherent
housing assembly in the form of the drive housing 5. The clamping
means 22 are in particular distributed in a multiple arrangement
around the longitudinal axis 6 in the manner of a flange joint,
lying preferably on a circle line concentric with the longitudinal
axis 6.
The drive diaphragm 12, which preferably has a circular external
contour, has an annular continuous outer edge section 23 concentric
with the longitudinal axis 6. The drive diaphragm 12 is fixed to
this outer edge section 23 so as to be immovable relative to the
drive housing 5. It is, however, not fixed directly to the drive
housing 5, but rather by axial clamping between first and second
insert bodies 24, 25, which are separate from the drive housing 5
and located in the housing interior 8 in an axially and radially
immovable manner.
The first insert body 24 sits coaxially in the first drive housing
part 15 and the second insert body 25 sits coaxially in the second
drive housing part 16. Each drive housing part 15, 16 bounds an
interior section 27, 28 of the housing interior 8, which interior
section 27, 28 is axially open towards the respective other drive
housing part 15, 16 via a front housing part opening 26 in the
joining region 17. As the front housing part openings 26 of the two
drive housing parts 15, 16 are in alignment with each other, they
complete each other to form the housing interior 8.
Each of the insert bodies 24, 25 is installed into the interior
section 27, 28 of the associated drive housing part 15, 16 through
the front housing part opening 26 and in particular inserted
axially. The installation depth is predetermined by cooperating
stop means. In concrete terms, for forming the stop means each
insert body 24, 25 has on the side remote from the joining region
17 at least one and preferably precisely one support section 31,
with which it bears against a mating support section 32, which is
preferably represented by a step at the inner surface of the drive
housing wall 7.
The axial length and the axial position of the insert bodies 24, 25
are chosen such that, when installed into the associated drive
housing part 15, 16, their axial front side is approximately flush
with the joining region 17. Each insert body 24, 25 is preferably
axially shorter than the interior section 27, 28 of the housing
interior 8 which accommodates it.
Each of the two insert bodies 24, 25 is in particular designed to
be annular and arranged to be coaxial with the longitudinal axis 6.
Each annular insert body 24, 25 radially encloses on the outside an
axially continuous interior identified as ring interior space 33
for easier differentiation. Each insert body 24, 25 has a front
side facing the drive diaphragm 12 and a rear side remote from the
drive diaphragm 12, the ring interior space 33 being open on the
front side via a front annular opening 33a and on the rear side via
a rear annular opening 33b. The front annular opening 33a of each
insert body 24, 25 is framed by an annular clamping section 34 of
the respective insert body 24, 25, which annular clamping section
34 is concentric with the longitudinal axis 6.
The drive diaphragm 12 projects with its outer edge section 23
axially between the facing clamping sections 34 of the two insert
bodies 24, 25, between which it is compressed axially and thus
clamped while forming a seal.
The flow of forces for the clamping force acting in this process
runs through the clamping means 22 between the two drive housing
parts 15, 16, from there via the axially mutually supporting
support sections 31 and mating support sections 32 into the two
insert bodies 24, 25, and from there via the two clamping sections
34 into the outer edge section 23 of the drive diaphragm 12.
The two insert bodies 24, 25 are therefore clamped together axially
and to the drive diaphragm 12 placed in between solely by the axial
force applied by the drive housing parts 15, 16 accommodating
them.
The sections of the two operating chambers 13, 14 which axially
adjoin the drive diaphragm 12 on both sides are each represented by
the ring interior space 33 of one of the two insert bodies 24, 25,
Each of these insert bodies 24, 25 defines a peripheral wall
section 35 of the associated first or second operating chamber 13,
14.
The peripheral wall section 35 adjoins the annular clamping section
34 directly in particular. It is expediently contoured such that
the ring interior space 33 has a larger diameter at the front side
of the insert body 24, 25 than at the rear side. In other words:
the front annular opening 33a has a larger cross-section than the
rear annular opening 33b.
The insert body 24, 25 is a one-piece component in particular and
preferably consists of a rigid plastic material. Other materials
are also possible, however, in particular aluminium or a
metal/polymer composite.
The two drive housing parts 15, 16 are expediently made of metal,
in particular of aluminium or stainless steel.
A preferred design of the insert bodies 24, 25, which is realised
in the illustrated embodiment, provides that the part which
directly forms a peripheral wall section 35 of an operating chamber
13, 14 is a radially inward inner ring section 36, which is
concentrically enclosed by a preferably hollow-cylindrical outer
ring section 37 at its radial outside. The outer ring section 37
likewise integrally adjoins the clamping section 34 defining the
front side of the insert body 24, 25. As the inner ring section 36
tends radially inwards towards the rear side, there is an
intermediate space 38 widening towards the rear side and open
towards the rear side of the insert body 24, 25 radially between
the two ring sections 36, 37. The intermediate space 38 can be
annular or limited locally to one or more points distributed along
the ring circumference.
The support section 31 is expediently represented by the rear free
end section of the outer ring section 37.
The insert body 24, 25 defines a radial inner surface 42 facing the
operating chamber 13, 14. This is expediently shaped in such a way
that it has, adjoining the clamping section 34, a convex inner
surface section 42a and, adjoining this, a concave inner surface
section 42b. If preferred, the radial inner surface 42 can be
represented by the inner ring section 36.
In the region remote from the clamped outer edge section 23, the
drive diaphragm 12 is deflectable in both directions of the
longitudinal axis 6 while being elastically deformed. This
deflecting movement of the drive diaphragm 12 is to be identified
as drive movement 43 and is indicated by a double-headed arrow. In
the drive movement 43, a power output section 44 of the drive
diaphragm 12 which is radially spaced from the outer edge section
23 can be deformed, while performing the drive movement 43, between
two maximally deflected positions, the first of which is
illustrated in the drawing. The distance between the two maximally
deflected positions defines the maximum stroke of the power output
section 44 and thus of the drive movement 43.
An output member 45 which is movable relative to the drive housing
5 in the direction of the longitudinal axis 6 extends in the drive
housing 5. The output member 45 is preferably designed to be
rod-shaped, which applies to the illustrated embodiment. The output
member 45 is guided in the housing for linear movement and passes
through the wall of the drive housing 5, thus having an output
section 46 which is accessible outside the drive housing 5. The
rod-shaped output member 45 is oriented coaxially with the
longitudinal axis 6.
The drive diaphragm 12 is secured to the output member 45 in the
housing interior 8 by its power output section 44. As a result, the
drive movement 43 is directly transmitted to the output member 45,
which can therefore be driven to perform an output movement 47
indicated by a double-headed arrow, which is relative to the drive
housing 4 and oriented in the direction of the longitudinal axis 6.
The output movement 47 can be tapped at the output section 46,
which in the illustrated embodiment is achieved by providing that
the output section 46 is drive-coupled to a valve member 48 of the
valve fitting 3 mentioned above. In this way, a valve member 48 can
be actuated, for example to optionally open up or block a fluid
flow through the valve fitting 3.
The drive movement 43 of the drive diaphragm 12 can be initiated by
a controlled application of fluid which can be realised by means of
a control passage structure 52 integrated into the drive unit 4.
The control passage structure 52 facilitates the controlled infeed
and discharge of a pressurised drive fluid relative to at least one
of the two operating chambers 13, 14. In the illustrated
embodiment, the control passage structure 52 is designed for a
controlled application of fluid to both operating chambers 13, 14,
but in practical applications it is used for the controlled
application of fluid to only one of the two operating chambers 13,
14, i.e. to the second operating chamber 14 located below the drive
diaphragm 12. The reason for this one-sided use of the controlled
application of fluid is that the diaphragm drive 2 of the
illustrated embodiment is designed to be single-acting and equipped
with a spring device 53 which constantly preloads the drive
diaphragm 12 towards one of its maximally deflected positions. In
the illustrated embodiment, the drive diaphragm 12 is spring-loaded
towards the first maximally deflected position which, in
combination with the illustrated valve fitting 3, causes a closed
position of the valve member 48, so that the valve assembly 1 is of
the "normally closed" type. In this context, the spring device 53
is located in the first operating chamber 13 and is designed as a
compression spring supported on the drive diaphragm 12 on the one
hand and on a first end wall 54 of the first drive housing part 15,
which completes the first operating chamber 13 on the side which is
axially opposite the drive diaphragm 12, on the other hand.
The diaphragm drive 2 can, however, alternatively be designed such
that the drive diaphragm 12 is preloaded by a spring device 53
towards the second maximally deflected position opposed to that
shown in FIGS. 3 and 4. In this case, the spring device 53 is
located in the second operating chamber 14 and is again supported
on the drive diaphragm 12 on the one hand and on the second end
wall 55 belonging to the second drive housing part 16 and located
axially opposite the drive diaphragm 12 on the other hand.
In the single-acting designs of the diaphragm drive 2, the drive
movement 43 and the resulting positioning of the drive diaphragm 12
and thus of the output member 45 are initiated by the controlled
application of fluid to that operating chamber 13, 14 which is not
equipped with a spring device 53. This is described below with
reference to the illustrated design, in which the spring device 53
is located in the first operating chamber 13.
It has to be said first that the drive unit 4 also comprises a seal
structure 56 acting as a seal between the drive housing 5 and at
least one of the two insert bodies 24, 25, which seal structure 56
preferably prevents an axial flow of drive fluid in the
intermediate region 57 between the insert bodies 24, 25 and the
drive housing 5. In this way, an uncontrolled transfer of operating
fluid between the two operating chambers 13, 14 by an external flow
around the two insert bodies 24, 25 can be eliminated.
When the drive diaphragm 12 is deflected axially by the application
of fluid to an operating chamber 13, 14, it is inflated to some
extent and can rest against the radial inner surface 42 of that
insert body 24, 25 towards which it is deflected. The described
design of the radial inner surface 42 avoids sharp edges which
could cause a premature wear of the diaphragm material and supports
the drive diaphragm 12 in a way which avoids its
overstretching.
The axial length of the two insert bodies 24, 25 is expediently
chosen such that the drive diaphragm 12 always remains axially
within the ring interior spaces 33 in its drive movement 43. The
two operating chambers 13, 14 nevertheless extend axially beyond
the rear side of the two insert bodies 24, 25, each including that
longitudinal section of the associated interior section 27, 28
which is located axially between the insert body 24, 25 and the
associated end wall 54, 55.
The control passage structure 52 used for applying fluid to one or
both of the operating chambers 13, 14 is formed at least partially
in the drive housing 5, preferably in the drive housing wall 7 of
the drive housing 5. By way of example, it comprises a first
control passage 58 in continuous fluid connection with the first
operating chamber 13 and a second control passage 59 in continuous
fluid connection with the second operating chamber 14. The first
control passage 58 is located behind the sectional plane in the
sectional view of FIG. 3 and is therefore indicated by a broken
line only.
The first control passage 58 terminates with a first connecting
port 58a towards an outer surface of the drive housing 5. In a
corresponding way, the second control passage 59 terminates with a
second connecting port 59a likewise towards an outer surface of the
drive housing 5. At least one and preferably both of the connecting
ports 58a, 59a is/are located at the first drive housing part 15,
by way of example on a terminating element 62 completing the first
drive housing part 15 on the side axially opposite the joining
region 17.
The first control passage 58 extends in the wall of the first drive
housing part 15 parallel to the longitudinal axis 6 and terminates
in a region axially spaced from the first insert body 24 into the
interior section 27 via an inner passage orifice 58b.
If the first control passage 58 is used for the controlled
application of fluid to the drive diaphragm 12, which does not
apply to the illustrated embodiment, a drive fluid can optionally
be fed into the first operating chamber 13 or discharged from the
first operating chamber 13 through the first control passage 58. A
dot-dash flow arrow 63 illustrates the fluid flow involved in this
process.
If, as in the illustrated embodiment, the actuating force acting on
the drive diaphragm 12 in the direction of its first maximally
deflected position is provided by a spring device 53, the first
control passage 58 is not used and can in this case be omitted
completely or used as a breathing passage.
If the first control passage 58 is used as intended, however, the
seal structure 56 prevents an unwanted fluid transfer from the
first operating chamber 13 into the second operating chamber 14
through the intermediate region 57, which is located radially
between the two insert bodies 24, 25 and the two drive housing
parts 15, 16.
The second control passage 59 connects the second connecting port
59a to the second operating chamber 14 while bypassing the two
insert bodies 24, 25.
In this context, the second control passage 59 has a first passage
section 59b, which starts at the second connecting port 59a, passes
through the wall of the first drive housing part 15 in its
longitudinal direction and terminates, in a region located radially
between the first insert body 24 and the first drive housing part
15, into a further passage section of the second control passage
59, which is represented by a first annular chamber 59c and located
concentrically between the first insert body 24 and the first drive
housing part 15.
This first annular chamber 59c forms an annular fluid duct chamber
64, which is a part of the second control passage 59 and extends
around the first insert body 24.
The first fluid duct chamber 64 is sealed axially by the seal
structure 56 on both sides. On the one hand, it is separated in a
fluid-tight manner from the first operating chamber 13 via a first
annular seal section 65 of the seal structure 56, on the other hand
towards the joining region 17 via a second annular seal section 66
of the seal structure 56. Each annular seal section 65 provides a
seal both in respect of the first insert body 24 and in respect of
the first drive housing part 15. Both seal sections 65, 66 are
expediently designed separate from the first insert body 24 and
from the drive housing 5 and in the illustrated embodiment consist
of annular sealing rings 67 held in receptacle grooves of the first
insert body 24.
Adjoining the first annular chamber 59c represented by the first
fluid duct chamber 64, the second control passage 59 continues in
the wall of the drive housing 5 with a third passage section 59d
composed of a sub-section formed in the first drive housing part 15
and a second sub-section formed in the second drive housing part
16, the sub-sections being in alignment in the joining region 17.
The first sub-section of the third passage section 59d communicates
with the first fluid duct chamber 64. The second sub-section of the
third passage section 59d communicates with a further passage
section of the second control passage 59, which is represented by a
second annular chamber 59e. The second annular chamber 59e is
arranged concentrically between the second insert body 25 and the
second drive housing part 16 in the interior section 28 of the
housing interior 8 formed in the second drive housing part 16 and
represents a second annular fluid duct chamber 68, which is axially
open towards the second operating chamber 14 on the one hand while
on the other hand being sealed axially towards the joining region
17 via a third annular seal section 69 of the seal structure 56.
The third annular seal section 69 seals radially between the second
insert body 25 and the second drive housing part 16, being
expediently a separate body in particular represented by a sealing
ring held in a receptacle groove of the second insert body 25.
An annular gap 72 between the second insert body 25 and the second
drive housing part 16 creates a permanent connection between the
second fluid duct chamber 68 and the second operating chamber 14,
offering the opportunity for optionally feeding a drive fluid into
the second operating chamber 14 or discharging it from the second
operating chamber 14 via the second connecting port 59a as
indicated by the flow arrow 73.
The annular gap 72 facilitates a communication of the second
control passage 59 with second operating chamber 14 axially outside
of the second insert body 25. As the second insert body 25--and
preferably the first insert body 24 as well--is/are annular,
however, drive fluid can be applied in a controlled manner to the
drive diaphragm 12 through the ring interior space 33 enclosed by
the second insert body 25. This offers the advantage that the wall
of the second insert body 25 and preferably that of the first
insert body 24 as well can be designed without an opening, which
applies to the illustrated embodiment. In the circumferential
direction of the longitudinal axis 6, the wall of each insert body
24, 25 is expediently closed, so that no fluid exchange is possible
through this wall.
The annular seal sections 65, 66, 69 are arranged coaxially with
and at a radial distance from one another. Corresponding to the
external shaping of the insert bodies 24, 25, they can have
different diameters.
The diaphragm drive 2 is in particular designed for operation with
compressed air as drive fluid. In principle, however, it can be
operated with other pressure fluids as well, in particular with
liquid pressure media.
At least one and preferably both of the connecting ports 58a, 59a
is/are expediently located at an external end face section 74 of
the first drive housing part 15. By way of example, this external
end face section 74 is provided at the terminating element 62
mounted on the end face of a base unit 75 of the first drive
housing part 15, the base unit 75 having a hood-shaped structure
and defining that interior section 27 of the housing interior 8
which is formed in the first drive housing part 15. The first end
wall 54 is a part of the base unit 75, being preferably fixed
detachably, however. The terminating element 62 is located axially
behind the first end wall 54. If we include the first terminating
element 62, the first drive housing part 15 is preferably
hood-shaped in design.
The second drive housing part 16 is in particular hood-shaped as
well, the second end wall 55 being preferably an integral part of
the second drive housing part 16. The rod-shaped output member 45
passes slidably through a wall opening 76 of the second end wall
55, which wall opening 76 expediently accommodates a guide sleeve
for the linear guidance of the output member 45 and a sealing ring
for dynamically sealing the output member 45 against the second
drive housing part 16.
The location of the drive diaphragm 12 on the output member 45,
which facilitates the transmission of drive forces, is expediently
based on additional fastening means 77. By way of example, the
fastening means 77 consist of two disc-shaped fastening plates 77a,
77b, which are perforated in the centre and secured to the output
member 45 in any desired manner, in particular by a welded
joint.
* * * * *